The blackbird family is hard to characterize because it includes such
diverse types: orioles, meadowlarks, grackles, cowbirds, and others. Most
have at least some black in the plumage, and their other colors run to
warmer tones, such as yellow, brown, and orange. All the species have
sharply-pointed bills. Most are more or less omnivorous. None is adapted
to extreme desert conditions, but several species make inroads to the
Sonoran Desert.

Great-tailed Grackle

Orioles in general are treetop birds, moving methodically through the
foliage in search of insects, often stopping at flowers to add some nectar
to their diet. In the lowlands of the Southwest, hooded orioles and Bullock’s
Orioles occur mainly as summer residents in riverside woodlands. The Hooded
Oriole has a special liking for palms, however, and it may be common in
desert cities where palms have been planted.

Great-tailed Grackles are recent arrivals in this region. Spreading north
through Mexico, they did not reach Arizona until 1936. Even today they
are closely associated with water, living near riversides, ponds, irrigated
farmland, or watered lawns. Sociable birds, they nest in colonies and
sleep in large communal roosts, where their cacophonous voices make them
a little too conspicuous for some tastes.

Cowbirds’ nesting behavior—or lack of it—makes them the most unpopular
of the blackbirds and, perhaps, the most interesting. Cowbirds lay their
eggs in the nests of other birds, leaving the unwitting hosts to hatch
the eggs and feed the young. In many cases, only the young cowbirds survive.
Cowbirds are seldom seen in natural desert areas in winter, when they
mostly forage in agricultural land; but in the breeding season, Brown-headed
Cowbirds and Bronzed Cowbirds infiltrate the desert (and most other habitats),
seeking nests to parasitize.

Habitat

All are known to occur in open to semi-open habitat including farms,
fields, river groves, thickets, and city parks.

Feeding

• Diet: The grackle’s varied diet includes plant matter, insects, reptiles,
small fish, aquatic invertebrates, and eggs and nestlings of other birds;
the two species of cowbirds feed mostly on seeds and insects.

• Behavior: These 3 species forage mainly by walking on the ground; the
grackle also forages in trees and shrubs, especially when looking for
eggs or nestlings. These birds generally feed in flocks.

Life History

The Great-tailed Grackle nests in colonies; both males and females may
have more than one mate. The nest site varies but is usually in dense
vegetation near water. The bulky, open, cup-shaped nest, which may be
a few feet to over 20 (7 m) above the ground, is made of twigs, weeds,
grass, rushes, and other available material. Bluish eggs (3-5) with brown
scrawls hatch in 13 to 14 days. The young, which are fed only by the female,
leave the nest about 3 weeks after hatching.

Both cowbird species are brood parasites, laying their eggs in other
birds’ nests where they are incubated by the host parents. In some areas
this parasitic behavior has greatly diminished song bird numbers.

The Bronzed Cowbird may lay 1 pale blue-green egg per day for several
weeks; the female may pierce the eggs of its host while depositing her
eggs. Nestlings are fed by the host and leave the nest 10 to 12 days after
hatching. Common host birds include orioles, towhees, and thrashers. Although
now rather common, the Bronzed Cowbird was not recorded in Arizona until
1909.

The Brown-headed Cowbird may lay one whitish spotted egg per day for
several weeks until 40 or more eggs have been laid; the female often removes
the eggs of its host before depositing her own. Nestlings are fed by the
host and leave the nest 10 to 11 days after hatching. Common host birds
include finches, warblers, and vireos. The Brown-headed Cowbird is known
to have parasitized over 200 species of birds with well over 100 species
known to have successfully raised cowbird young.

Feathers

The typical feather with a shaft and vane is called a contour feather.
These feathers occur on the body, the wing, and the tail. They form the
outer covering of the bird providing protection from sun, wind, rain,
and abrasion. The contour feathers on the wing and tail are primarily
involved in promoting flight. Down feathers are frequently found underneath
the body contour feathers. These feathers have a minute shaft; barbules
lack hooks and flanges. The result is a very “downy”feather. Their position
under the protective body contour feathers provides an air trap that facilitates
heat conservation. There are several other types of feathers that have
specialized functions. Semiplumes, filoplumes, bristles, and powder down
are examples.

Habitat

Hooded Oriole: Open woods, tree plantations, palms, city parks, and suburbs;
favors groups of palms for nesting, even when these trees are in cities.

Bullock’s Oriole: Common and widespread in the west, this species inhabits
woodland, isolated groves of trees, streamside growth (especially cottonwood),
farms, ranches, city parks, and suburbs.

Feeding

• Diet: Both species feed primarily on insects and take lesser quantities
of fruit and nectar.

• Behavior: Both species forage by searching for insects in trees and
shrubs; flowers are visited for nectar; feeders with sugar-water also
attract orioles. The Hooded Oriole is a slow and deliberate forager, which
makes it a rather easy bird to observe in the field.

Life History

The nest of orioles is often parasitized by cowbirds; the aggressive
young cowbird usually receives the most food which eventually starves
the oriole nestlings.

Bullock's Oriole

The Hooded Oriole lays 3 to 5 bluish or grayish-white, spotted eggs in
a long, hanging, woven pouch that it enters from the top. The nest usually
hangs in a palm, large yucca or a eucalyptus tree. Incubation is by the
female and takes 12 to 14 days; both parents feed the nestlings.

The Bullock’s Oriole lays 3 to 6 bluish-white to pale gray, spotted eggs
in a hanging pouch firmly attached to a tree branch. Incubation is by
the female and takes 12 to 14 days; both parents feed the nestlings.Young
leave the nest about 12 to 14 days after hatching.